Latching device

ABSTRACT

A LATCH FOR A SELF-CLEANING OVEN AND COMPRISING A HANDLE OPERABLE TO MOVE A BOLT ALONG A FIRST PATH INTO ENGAGEMENT WITH A STRIKE ON THE OVER DOOR AND THEN INWARDLY ALONG A SECOND PATH TO A LATCHED POSITION TO DRAW THE DOOR IN TIGHTLY AGAINST THE OVEN CABINET. A SPRING ACTING ON THE BOLT NORMALLY HOLDS THE BOLT FOR MOVEMENT IN ITS FIRST PATH AND PREVENTS THE BOLT FROM MOVING INWARDLY TO ITS LATCHED POSITION UNLESS THE DOOR IS CLOSED AND THE   BOLT ACTUALLY ENGAGES THE STRIKE TO CREATE A FORCE OVERCOMING THE SPRING FORCE.

R. V. FOWLER LATCHING DEVICE Feb. 22, 1972 1 t; a y w m; m mVw wOriginal Filed Nov. 4, 1966 Feb. 22, 1972 FOWLER Re.

LATCHING DEVICE Original Filed Nov. 4, 1966 5 Sheets-Sheet 2 70 253 WQoiand pwler R. V. FOWLER LATCHING DEVICE Feb. 22, 1972 5 Sheets-Sheet 3Original Tiled Nov. 4, 1966 6 mvaroTom Qcianol \ff 'bwler MM I J TTovzmmyf Feb. 22, 1972 v FOWLER Re. 27,291

LATCHING DEVI CE 5 Sheer.sSheet 4 Original Tiled Nov. 4;, 1966 R v\ \l 8/V/A A Qolqnd \frowlev- 21 0%,WWJJM R. V. FOWLER LATCHING DEVICE Feb.22, 1972 5 Sheets-Sheet 5 Original Filed Nov. 4, 1966 0 MVE: mrora. 5 mFowler 2Jo,)JM:M, Yul-4 W cy ww-orawzwa/ United States Patent 27,291LATCHING DEVICE Roland V. Fowler, Louisville, Ky., assignor to AmerockCorporation, Rockford, Ill. Original No. 3,410,591, dated Nov. 12, 1968,Ser. No. 592,137, Nov. 4, 1966. Application for reissue Mar. 12,

1970, Ser. No. 18,870

Int. Cl. Ec 5/00, 19/10 U.S. Cl. 292-113 18 Claims Matter enclosed inheavy brackets II] appears in the original patent but forms no part ofthis reissue specification; matter printed in italics indicates theadditions made by reissue.

ABSTRACT OF THE DISCLOSURE A latch for a self-cleaning oven andcomprising a handle operable to move a bolt along a first path intoengagement with a strike on the oven door and then inwardly along asecond path to a latched position to draw the door in tightly againstthe oven cabinet. A spring acting on the bolt normally holds the boltfor movement in its first path and prevents the bolt from movinginwardtly to its latched position unless the door is closed and the boltactually engages the strike to create a force overcoming the springforce.

This invention relates to a latch particularly adapted for use inlatching the door of an appliance such as a self-cleaning oven or anautomatic dishwasher in tightly closed condition prior to operation ofthe appliance and includes generally an operating handle for moving alatching bolt first outwardly along a first predetermined path from aretracted position to an extended position to engage a strike and theninwardly along a second predetermined path to a latching position todraw the door into a tightly closed position. The inward or draw-inmotion of the bolt along the second path toward the latching position isused to actuate a control switch conditioning the appliance foroperation and such motion is blocked when the door is not closed inorder to prevent activation of the appliance even though the operatinghandle should happen to be moved.

The general object of the present invention is to provide a new andimproved latch of the foregoing character which is simpler inconstruction, more effective and trouble-free in operation and, at thesame time, has a longer service life than prior latches used for relatedpurposes.

A further object is to block the draw-in motion of the bolt until thelatter engages the strike and to utilize the strike for causing thedraw-in motion thereby to insure that the bolt cannot be moved inwardlyto its latching position when the door is open.

A more detailed object is to provide a novel blocking member normallydisposed in an active position to help block inward movement of the boltand movable to an inactive position to permit such movement in responseto engagement of the bolt with the strike.

Still another object is to return the bolt of the foregoing latch to itsretracted position automatically after the bolt is moved to its extendedposition without engaging the strike.

The invention also resides in the novel coaction between the bolt andthe blocking member enabling positive latching and sealing of the doorin spite of possible misalinernent between the bolt and the strike.

Other objects and advantages of the invention will become apparent fromthe following detailed description taken in connection with theaccompanying drawings, in which FIG. 1 is a fragmentary verticalcross-section of an appliance equipped with a latch embodying the novelfeatures of the present invention.

FIG. 2 is a schematic plan view of the appliance and latch andillustrating the different positions of the operating handle.

FIG. 3 is an enlarged side elevation of parts shown in FIG. 1.

FIG. 4 is a fragmentary plan view of the latch and showing the partswith the bolt in its retracted position.

FIG. 5 is a fragmentary cross-section taken substantially along the line5-5 of FIG. 4.

FIG. 6 is a view similar to FIG. 4 and showing the parts with the dooropen and the bolt in its extended position.

FIG. 7 is a view similar to FIG. 4 and showing the parts with the doorclosed and the bolt in its extended position.

FIG. 8 is a view similar to FIG. 4 and showing the parts with the boltin its latching position.

FIG. 9 is a fragmentary cross-section taken substantially along the line9-9 of FIG. 8.

FIG. 10 is a fragmentary cross-section taken substantially along theline 10-10 of FIG. 3.

FIG. 11 is an enlarged perspective view of the block ing member.

FIG. 12 is an enlarged perspective view of the bolt.

FIG. 13 is an enlarged fragmentary cross-section taken substantiallyalong the line 1313 of FIG. 7.

FIG. 14 is a view similar to FIG. 4 but showing a modification of thelatch.

'- FIG. 15 is a fragmentary cross-section taken substantially along theline 1515 of FIG. 14.

FIG. 16 is a view similar to FIG. 4 but showing still a furthermodification of the latch.

:As shown in the drawings for purposes of illustration, the invention isembodied in a latch 10 mounted within the cabinet 11 of an appliancesuch as a self-cleaning oven and including a bolt 13 selectivelyengageable with a strike 14 on the oven door 16 to latch the door in atightly closed position prior to operation of a high-temperature heatingunit (not shown )for burning off food and grease from the oven walls. Insuch a latch, an operating handle 17 is pivoted on a latch base ormounting. bracket 19 and is connected to the bolt which is guided on thebase so that counterclockwise swinging of the handle from an unlatchedposition to a latched position and then to a tightsealing position (seeFIG. 2) results in a two-step movement of the bolt to latch the door. Asthe handle is swung between its positions, the bolt first movesoutwardly along a first predetermined path from a retracted position(FIG. 4) to an extended position (FIG. 7) in which an outer end 20 ofthe bolt is disposed in engagement with the strike, and then movesinwardly along a second predetermined path to a latching position (FIG.8) to draw the door into tight-sealing relation with the cabinet. Toprevent activation of the high-temperature cleaning unit when the dooris open or free to open, a safety switch 21 (FIGS. 1 and 2) in thecontrol circuit of the unit is .ctuated-by the draw-in motion of thebolt and condiions the circuit for operation only when the door is losedand tightly sealed.

In this instance, the latch base 19 is a generally recangular sheetmetal plate disposed in a horizontal posiion above an insulated top wall23 (FIG. 1) of the oven hamber and formed with upstanding flanges 24(FIG. 8) round its peripheral edges. The outer flange lies against nd issecured to the inner side of a frame strip 25 (FIG. extending along thefront of the cabinet 11, and the ide flanges are formed with outturnedmounting wings 6 (FIGS. 2 and 8) fastened to the cabinet by screws 27.,he operating handle 17 is substantially L-shaped in levation andincludes a horizontal arm 29 disposed eneath the base plate 19 andpivotally connected to the atter by a rivet 30. Formed integrally withand upstanding rom the outer end of the horizontal arm is asubstantially ertical arm 31 passing upwardly through a relatively tidearcuate slot 33 punched out of the base plate to acommodate swinging ofthe handle about the rivet. At its ree end, the vertical arm of thehandle is connected to spring metal extension 34 (FIGS. 1 and 3) mountedantilever fashion and projecting outwardly through an rcuately curvedand elongated slot 35 (FIGS. 1, 3 and formed in a bezel 36 fastened tothe front of the abinet 11. A knob 37 mounted on the outer end of thextension facilitates gripping of the handle as it is swung etween itspositions.

As shown most clearly in FIGS. 1 and 3, the resilient andle extension 34is inclined downwardly and forwardly 1rough a slight angle and bearsagainst the bottom edge 1: the slot 35 in the bezel 36 thereby todevelop sufficient rictional force to hold the handle 17 in any positionto which it is swung. To protect against inadvertent move- 1ent of thehandle from its unlatched and tight-sealing ositions, a detent notch 39(FIGS. 2, 3 and is armed in the bottom edge of the slot 35 at each endaereof to receive the extension 34 when the handle is 1 its extremepositions. With this arrangement, the ex- :nsion must be flexed upwardlyand out of the notches s shown in phantom in FIG. 3 in order to swingthe andle between the unlatched and tight-sealing positions. heextension rides along the bottom edge of the slot 5 during such swingingand, upon reaching the opposite xtreme position, springs downwardly intothe adjacent otch with a positive snap action to hold the handle :curelyin place.

The bolt 13 is a sheet metal stamping disposed above the ase plate 19and formed with an inner main body poron 40 (FIGS. 4 and 12) pivotallyconnected to the mer end of the horizontal arm 29 of the handle 17 y apin 41 (FIGS. 4 and 5) fastened securely to the bolt nd projectingdownwardly therefrom through a slot 43 )rmed in the base plate andarcuately curved about the xis of the rivet 30. At its lower end, thepin is loosely :ceived within a hole in the horizontal arm so that theolt may swing relative to the handle as the latter is .vung between theunlatched and tight-sealing positions ith the pin 41 traveling in theslot 43. Angularly offset nd projecting generally outwardly from thebody 40 of the olt is an elongated neck 44 (FIG. 12) which terminates 1the outer end for engaging the strike 14 on the oor 16. The outer end ofthe bolt is disposed behind the ront of the cabinet 11 and inside theouter flange 24 11 the base on the base plate 19 when the handle is in sunlatched position and the bolt is in its retracted osition (see FIG. 4)and therefore will not be struck y the door when the latter is closedduring normal coking operations when the latch is not in use. As theandle is swung toward its latched position (FIG. 7), its lotion isimparted to the bolt which moves to the ex- :nded position with theouter end 20 projecting outardly through alined slots formed in theouter flange 4 and the frame strip during such movement. In

addition, the outer end passes into a slot 45 (FIG. 7) formed in theinner liner of the door and engages the strike 14 which, in thisinstance, is formed by the right end wall of the slot 45 (as viewed fromthe front of the latch in FIG. 7). Upon movement of the handle from itslatched position to its tight-sealing position (FIG. 8), the outer endof the bolt moves inwardly to its latching position thereby to seal thedoor tightly against the cabinet 11.

Since activation of the high-temperature cleaning unit with the door 16in an open position would allow smoke and odors to escape from thecabinet 11 or might cause a sudden flame, the safety switch 21 for theunit is arranged to be actuated by the inward or draw-in motion of thebolt 13 and such motion is blocked when the door is not closed. Thus,when the door is open, the bolt cannot be moved inwardly from theextended position (FIGS. 6 and 7) to the latching position (FIG. 8) toactuate the switch and the cleaning unit thereby is disabled.

In accordance with the present invention, the bolt 13 is held formovement along the first path from the retracted position (FIG. 4) tothe extended position (FIGS. 6 and 7) and is positively blocked frommoving inwardly along the second path to the latching position (FIG. 8)until the bolt engages the strike 14. Moreover, engagement of the boltwith the strike frees the bolt from movement along the first path andcauses the bolt to shift to movement along the second path to thelatching position. Accordingly, the bolt cannot move inwardly until itengages the strike, and actuation of the switch 21 thus is impossiblewhen the door 16 is in an open position and the strike is disposedremotely from the bolt.

To achieve the foregoing ends, the bolt 13 is formed with a guideelement 46 (FIGS. 4 and 12) which is held against a guide element 47(FIG. 4) on the base plate 19 as the handle 17 is swung between itsunlatched and latched positions. During such swinging of the handle, theelements 46 and 47 coact to guide the outer end 20 of the bolt outwardlyalong a substantially arcuate path from the retracted position (FIG. 4)to the extended position (FIG. 7 When the door 16 is closed, the outerend engages the strike 14 and such engagement causes the guide element46 to move away from the guide element 47 (FIG. 7) thereby to permit thebolt to move inwardly to the latching position (FIG. 8) as the handle isswung from its latched position to its tight-sealing position. When thedoor is open, however, and the bolt is moved to its extended positionwithout engaging the strike as shown in FIG. 6, the guide elementsremain against each other to block both inward movement of the bolt tothe latching position and continued swinging of the handle toward itstight-sealing position.

In the present instance, the guide element 46 is the convex edge of anarcuately curved portion 49 (FIG. 12) of a slot 50 formed in the bolt13, and the guide element 47 is a headed stud rigid with and upstandingfrom the base plate 19 and projecting into the slot 50. To hold theconvex edge 46 against the stud 47, a coil spring 51 (FIGS. 1 and 2) istelescoped over an elongated rod 53 extending rearwardly from the boltand slidably guided through a bracket 54 mounted on the upper side of arear wall 55 of the cabinet 11. The spring is contracted between anupstanding flange 56 integral with the bracket and a stop 57 rigid withthe rod so as to urge the rod outwardly or to the left. The effectiveforce of the spring is directed from the rod to the bolt through aconnecting point 59 located to the left of the pivot pin 41 (as viewedfrom the front of the latch) connecting the bolt to the short arm 29 ofthe handle 17 and thus urges the bolt counterclockwise about the axis ofthe pin to force the convex edge 46 against the stud 47.

Initially, the bolt 13 is disposed in its retracted position (FIG. 4)with the stud 47 disposed at the inner end of the slot 50 in the bolt.As the handle 17 is swung about the rivet 30 from its unlatched position(FIG. 4) to its latched position (FIG. 6), the bolt simultaneouslyswings about the axis of the pin 41 so that'the outer end 20 of the boltmoves from the retracted position (FIG. 4), outwardly along the frontofthe outer flange 24, and to the extended position shown in FIGS.6=arid 7 in substantial alinement with the position of the strike l4when the door 16 is closed. During, such movement, the convex edge 46 ispressed against and moves along the stud 47 to define the path that theouter end 20 follows. When the outer end of the bolt reaches theextended position with the door in an openposition as shown in FIG. 6,continued swinging of the handle through ashort arc toward thetight-sealing position simply moves an outer end 60 (FIGS. 6 and 12) ofthe arcuate portion 49 of the slot 50 against the stud 47. Engagement ofthe outer detent end 60 of the slot with the stud prevents furthercounterclockwise movement of the handle beyond the position shown inFIG. 6 and, more importantly, blocks inward movement of the bolt to thelatching position shown in FIG. 8. The bolt remains in theextended'blocked position '(FIG. 6) and must be returned to. theretracted position by clockwise swinging of the handle before the door'16 can be shut and latched closed.

When the door16 is in a closed position, counterclock- Wise swinging ofthe handle from the unlatched position to the latched position againmoves theibolt 13 from the retracted position(FIG. 4) to the extendedposition in the same manneras described above; Upon reaching theextended. position, however, a relatively straight portion 61 of theouter end 20 of the bolt engages the strike 14 as shown in FIG. 7, and ahook 62 adjacent the straight portion moves alongside the outerside ofthe strike so that the door is latched, but not sealed tight, and cannotbe opened without retracting the bolt. Engagement of thestraight'portion 61of the bolt with the strike, along with furthermovement of the handle toward the tight-sealing position, causes thestraight portion 61 to pivot on the strike and simultaneously to slideinwardly along the strike. This compound motion forces the main bodyportion 40 of the bolt sharply to the left (as viewed from the front ofthe latch) and pulls the convex edge 46 of the slot 50 in the bolt awayfrom the stud 47 against the action of the spring .51. In addition, thehook 62 moves inwardly in a substantially straight line and engages theouter side of the strike ('FIG. 8) to draw the door 16 intotight-sealing relation with the cabinet 11.

Toaccornmodate the compound sliding and pivoting motion of the bolt: 13occurring as an incident to engagement with, the strike, 14, the slot 50in the bolt is formed with arelatively straight outwardly extendingportion 63 (FIGS. .4 and 12) intersecting the :arcuate portion 49 justinwardlv of the oiiter detent end 60 of the arcuate portion; Theoutwardly extending slot portion 63 travels along the su d. 47, as thebolt'js moved from the extended position shown in 7 to .the latchingposition shown in FIG. 8. The width of-the outwardly extending slotportion is considerably greater than the diameter of the stud, hereinabout /a of an inch greater, and thus the compound inward movement ofthe bolt toward the latching position may'begin at differentpointsfalong the path of travel from the retracted-position to theextended position depending upon the lateraldisposit'ion' of the strike14. As a result, the strike may be misalined laterally as much as A ofan inch and :the latch still will function properly. It willbe apparentfrom the foregoing that inward shifting o f'the bolt 13 to the latchingposition is dependent upon whether or not the door 16is closed and thestrike 14 is in place Whenthe handle is operated. When the door is open,the spring 51 holds the convex slot edge 46 against the stud 47,. andthese elements, along with the outer detent end of the slot 50, preventthe bolt from. moving inwardly from the extended position to thelatching position. If the door is closed, the bolt engages the strikeand the force resultingfrom suchengagement overcomes the spring forceand j'separates'the guide elements 46 and 47 While shifting the boltinwardly to the latching position.

An important advantage is gained by the placement of the slot and thestud 47 so that the arc of rotation of the operating handle 17 necessaryto move the bolt 13 through its motions is reduced to about degreeswithout reducing the handle motion available to effect the drawing-in ofthe bolt and the tight sealing of the door 16. As shown most clearly inFIGS. 4, 6 and 7, the stud and the convex edge 46 of the slot 50 arespaced a greater distance from the rivet 30 than from the pin 41. Thus,during movement of the bolt from the retracted position to the extendedposition, the bolt travels at a greater angular velocity than the handleand, as a result, movement of the handle through a 30 degree are to thelatched position is effective to move the outer end 20 of the boltthrough approximately a 50 degree are to the extended position.Accordingly, a substantial portion of the full arc of the handleremains, herein about 30 degrees, and is utilized to draw the doorinwardly toward the cabinet 11 and into sealing engagement with theusual sealing gasket (not shown). Since the work done is equal to theforce exerted times the distance moved, it will be apparent that the useof an arc of substantial length to effect the draw-in motion minimizesthe force required to close and seal the door.

The present invention also contemplates the provision of a novelblocking member 64 (FIGS. 4 and 10) to help block inward movement of thebolt 13, to actuate the switch 21 in response to such inward movement,and to cooperate with the bolt to promote positive latching action whileaccommodating misalinement of the strike 14. Herein, the blocking memberis a lever pivotally connected near its inner end on the inner end ofthe main body 40 of the bolt by a rivet 65 rigidly fastened in a hole 66FIG. 12) in the bolt and projecting upwardly and loosely through a hole67 (-FIG. 11) in the lever 64.

When the bolt 13 is positioned as shown in FIGS. 4 and 6, the lever 64completely overlies the bolt and is prevented from clockwise swingingrelative to the bolt by an abutment surface 69 (FIGS. 4 and l1) on theouter end of the lever engaging a lug 70 (FIGS. 4 and 12) upstandingfrom the bolt. The lever thus, in effect, is rigid with the bolt andserves to transmit the force of the spring 51 to the bolt. For thispurpose, the connecting point 59 directing the spring force from theelongated rod 53 to the bolt is a rigid post projecting upwardly fromthe lever just to the left of the pivot pin 41 (as viewed from the frontof the latch) and pivotally connected to the inner end of the rod.Accordingly, the spring 51 urges the rod outwardly and the spring forceacts directly on the lever 64 tending to swing the latter clockwiseabout the rivet 65 while also acting through the lever and on the boltto urge the bolt counterclockwise about the pin 41.

In this instance, the lever 64 is formed with a slot 71 (FIGS. 4 and 11)having an arcuately curved portion 73 which is slightly wider than thearcuate portion 49 of the slot 50 in the bolt 13. In addition, the slot71 in the lever is formed with an outwardly extending portion 74intersecting the outer end of the arcuate portion 73, the outwardlyextending portion 74 of the lever slot 71 being considerably narrowerthan the outwardly extendingportion 63 of the bolt slot 49 and having awidth approximately of an inch greater than the diameter of the stud 47.

In the retracted position (FIG. 4) of the bolt 13 and as the bolt isbeing moved to the extendedposition (FIG. 6), the lever 64 is disposedin an active position in which the arcuate portion 73 of the lever slot71 overlies and is alined with the arcuate portion 49 of the bolt slot50 while the outwardly extending portion 74 of the lever slot 71 isoutwardly offset from theoutwardly extending portion 63 of the boltslotSO. As a result, the intersection between the arcuate and outwardlyextending portions 49 and 63 of the bolt slot 50 is covered and blockedby an edge surface 75 on the lever (FIGS. 4 andlll)'formed near thejunction: of the arcuate and outwardly extending portions 73 and 74 ofthe lever slot 71. During movement 3f the bolt from the retractedposition to the extended position, the lever moves bodily with the boltdue to the engagement with the lug 70 with the abutment surface 69 andif the bolt fails to engage the strike 14, the lever simply remains in astationary active position relative to the bolt as the outer detentportion 60 of the bolt slot 50 engages the stud 47 to prevent furthermovement of the bolt. It will be seen that, in addition to the springforce pressing the convex edge 46 of the bolt slot 50 against the stud47 to preclude movement of the bolt to the latchmg position, the edgesurface 75 on the lever extends across the intersection between thearcuate and outwardly extending portions 49 and 63 of the bolt slot 50thereby positively blocking any movement of the outwardly extendingportion 63 along the stud 47. Accordingly, it is impossible to move thebolt to the latching position.

When the bolt 13 moves to the extended position and the outer end 20engages the strike 14 (FIG. 7), the bolt substantially swings about thestrike and the main body 40 of the bolt begins moving to the left. Suchinitial leftward movement draws the edge surface 75 of the lever 54against the stud 47 so that the lever is prevented from moving bodilywith the bolt and, at the same time, is swung counterclockwise about theaxis of the rivet 65 inc to the camming action caused by engagement ofthe :dge surface 75 with the stud 47. As a consequence, the .ever swingsto an inactive position (FIGS. 7 and 8) in which the outwardly extendingportions 74 and 63 of the .ever slot 71 and the bolt slot 50,respectively, are alined and the intersection between the arcuate andoutwardly extended portions 49 and 63 of the bolt slot 50 is unalocked.The bolt thus is freed for complete movement the latching position(-F-IG. 8) with the outwardly extending portions 63 and 74 travelingalong the stud 47.

In addition to helping the spring 51 block movement )f the bolt 13 tothe latching position, the lever 64 also :oacts with the bolt tomaintain the parts of the latch relatively tight with respect to eachother while still pernitting the latch to function properly even throughthe ;trike 14 is misalined due to manufacturing or installation iefects.Because the outwardly extending portion 63 of :he bolt slot 50 isconsiderably wider than the stud 47, :he movement of the bolt to thelatching position may new at various points with the strike disposed indifferent lateral positions on the door 16. Since the outwardlyextending portion 74 of the lever slot 71 is about the same width as thestud, however, the bolt is prevented from noving indiscriminatelyrelative to the stud in spite of :he clearance between the stud and theoutwardly ex- :ending portion 63 of the bolt slot 50. Moreover, theipring 51 acting through the rod 53 and the lever acts :0 develop adesired amount of friction within the pivotal :onnections 30, 41 and 65of the latch parts thereby to :liminate undue looseness between theparts and to pronote good latching action.

Another important function of the lever 64 is to actuite the safetyswitch 21 in response to the inward movenent of the bolt 13 to thelatching position. To this end, :he switch is mounted on the bracket 54(FIGS. 1 and 2) it the rear of the cabinet 11 and includes an operatingllm 77 in the form of a fiat spring plate disposed imnediately behindthe rod 53. The rod moves inwardly or 'earwardly sufficiently far todepress the arm and actuate :he switch only when the lever 64 pivotsrelative to the Jolt 13 as an incident to the bolt moving to thelatching Josition. As shown most clearly in FIG. 6, the distance a)etween the axis of the rivet 30 and the post 59 taken rlong a straightline extending through the rod 53 and he post is approximately 1 incheswhen the door 16 open the bolt is blocked from moving forward toward .helatching position. When the bolt is blocked, the rod us not traveledrearwardly sufliciently far to depress the )perating arm 77 fully andactuate the switch 21. As soon the bolt begins moving to the latchingposition after engaging the strike 14, the lever 64 swingscounterclockwise through a short arc about the rivet 65 (see FIG. 7)thereby moving the rod rearwardly so that the corresponding distance bbetween the rivet 30 and the post 59 increases to 1% inches. This slightrearward movement of the rod is effective to close the switch therebyconditioning the cleaning unit for operation as an incident to the doorbeing safely latched. When the handle 17 has been swung fully to thetight-sealing position and the bolt has been moved fully to the latchingposition (FIG. 8), the lever is permitted to swing clockwise through a'short are about the rivet 65 under the influence of the spring 51 fromthe FIG. 7 position to the FIG. 8 position due to an inclined reliefportion 79 (FIGS. 7 and 11) formed at the outer end of the outwardlyextending portion 74 of the lever slot 71. Such clockwise swinging ofthe lever enables the rod to move outwardly a short distance to relievesome of the pressure on the switch arm 77 butnot sufficiently far toopen the switch 21. 1

In order to prevent the door 16 from being opened while the switch 21 isclosed and the cleaning unittis operating, a thermostatically operatedsafety device 80 (FIGS. 1, 5, and 9) is mounted in the cabinet 11beneath the base plate 19 of the latch 10. Herein," the 'safety deviceincludes an upright pin 81 which pops upwardly through a hole 83 (FIG.9) in the base plate when temperature within the oven is above 320degrees Fahrenheit. If the oven is being used for normal cooking operations and the bolt 13 is in the retracted position (FIG. 4) the pin 81,upon popping up through the hole 83, projects through a hole 84 (FIGS.4, 5, and 12) in the bolt to prevent the bolt from being moved from theretracted position and to prevent inadvertent operation of the cleaningunit. When the bolt is in the latching position (FIG. 8) and thecleaning unit is in use, the pin 81 extending through the base plate 19engages an ear 85 (FIGS. 8,- 9', and 12) on the bolt thereby blockingmovement ofthe bolt from the latching position and opening of the door'16 until the temperature of the oven drops below 320 degrees. v

A modified form of the latch 10 is shown in FIGS. 14 and 15 in whichthe-bolt 13, instead of-remaining in its extended blocked position ifthe strike 14 is not in place, is returned automatically to itsretracted position by the action of the spring 51. For this purpose, thedownwardly inclined cantilever spring extension 34 of the handle 17 isreplaced with a horizontal extension 34' of relatively rigid metalvertically centered between the upper and lower edges of a slot 35formed in a bezel 36'. Because the frictional force developed by thespring extension 34 is eliminated and because the post 59 which directsthe force of the coil spring 51 from the lever 64, through the bolt 13and to the handle 17 is located to the right of the rivet 30 (as viewedfrom the front of the latch) when the bolt is in its retracted andextended positions, the coil spring tends to swing the lever, the boltand the handle clockwise about the axis of the rivet 30. Accordingly,when the handle and bolt are moved from their unlatched andretracted-positions, respectively, shown in phantom in FIG. 14 and aremoved to the latched and extended positions shown in full Withoutengaging the strike, the spring Slimmediately returns the handle and thebolt back to the-unlatched and retracted positions as soon as the handleis-manually released. The bolt thus will be disposedin'the retractedposition behind the front of the cabinet automatically before the door16 is closed thereby avoiding damage to the bolt.

After the door 16 has been closed and as the bolt 13 is moved to thelatching position (FIG. 8), the post 59 passes across a straight line.extending between the rivet 30 and the spring 51 causing the latter tourge the bolt, the lever 64 and the handle 17 counterclockwise about therivet 30. The bolt and the handle thus are held securely in theirlatching and tight-sealing positions until the handle is intentionallymoved back toward its unlatched position..In a spring-back latch of thistype, the lever 64 not only serves to enhance the' latching action andto actuate the switch 21 but also properly locates the force of thespring 51 relative to the handle 17 so that the latter will be returnedto the unlatched position if the door is opened and will be held in thetight-sealing position when the door is closed. Except for thedifferences in the construction of the handle and the bezel, the latchshown in FIGS. 14 and 15 is identical to the previously describedmodification.

Still another embodiment of a novel latch constructed in accordance with.the present invention is shown in FIG. 16 in which the blocking lever64 is eliminated. In this. instance, the convex guide edge 46 of thebolt slot 50 is pressed against the guide stud 47 by a resilientlyyieldable contractile spring 90 stretched between one of the sidesflanges 24 (not visible in FIG. 16) and a lug 91 upstanding from thebolt .13 and disposed outwardly of the pivot pin 41. As the handle 17 isswung to the latched position shown in full without the outer end 20 ofthe bolt engaging the strike "14, the bolt pivots about the pin 41 andmoves in a path defined by the convex edge 46 1'1ntilthe' outer 'detentend 60- of the slot 50 engages the stud 47 to block inward movement ofthe bolt tothe latching position. When the outer end 20 engages thestrike, however, the compound pivoting and sliding movement of the 'boltproduced by such engagement in conjunctionwith continued. swinging. ofthe handle toward the tight-sealing position shown in phantom causes themain body 4-0 of the bolt to move sharply to the left thereby pullingthe convex edge 46 away from the stud and stretching "the spring 90.Theo-utwardly extending portion 63 of the bolt slot 50 then travelsalong the stud to permit complete inward movement of the bolt to thelatching position. A safety switch may be actuated as an incident to theinward movement by a rod 93 connected to a post 94 projecting upwardlyfrom the main body of the bolt. In this modification, the spring. 90presses the edge 46 against the stud 47 to restrict movement of the boltalong a first path from the retracted position to the extended position,and then the spring is disabled as a result of engagement of the boltwith the strike to enable the bolt to move inwardly along the secondpath to the latching position. The basic principle of operation is thesame as in the previous modification with the/primary distinction beingthat the advantages gained by the lever 64 are not present.

I claim .as my invention:

1. In combination with an appliance cabinet formed with an accessopening, a door for closing the opening, and'a strikeon'the door forlatching the door in a closed position adjacent the cabinet, theimprovement comprising, a latch having a base mounted within thecabinet, an operating handle having an inner end pivoted on said base.and an opposite end extending outwardly beyond the cabinet, said handlebeing swingable about a first axis between angularly spaced unlatched,latched and tight-sealing positions, a latching bolt mounted on saidhandle for swinging relative to the latter about a second axis v's'paeedinwardly from said first axis and having an outer end engageable withthe strike to latch the door, said bolt being formed with a slot havinga curved portion and having an outwardly extending portion intersectingsaid curved portion, a guide member on said base and projectingintosai'd curved portion of said slot as said handle is swung from saidunlatched position to said latched position thereby to guide said boltfor movement from a retracted position with said outer end beside thecabinet to an extended position with said outer end 'spaced-T'outwardlyfrom the cabinet :to engage the strike, said guide member projectinginto said outwardly extending portion of said slot as said handle isswung from said latched position to said tight-sealing position therebyenabling movement of said bolt from said extended position toa latchingposition with said outer end shifted inwardly toward the cabinet to drawin the door, a lever pivoted on said bolt and disposed in a normalactive position blocking the intersection between said curved andoutwardly extending portions of said slot as said bolt is moved fromsaid retracted position to said extended position thereby to preventmovement of the bolt to said latching position and swinging of saidhandle to said tight-sealing position when said outer end moves to orbeyond said extended position Without engaging the strike, and a camsurface on said lever engageable with said guide member as an incidentto said outer end engaging the strike thereby to swing the lever into aninactive position unblocking said intersection to permit movement ofsaid bolt to said latching position and swinging of said handle to saidtight-sealing posltion.

2. A latch as defined in claim 1 in which said lever is formed with aguide slot having a curved portion alined with the curved portion in theslot in said bolt when said lever is in said active position.

3. A latch as defined in claim 2 in which said guide slot has anoutwardly extending portion intersecting said curved portion and alinedwith the outwardly extending portion in the slot in said bolt when saidlever is in said inactive position.

4. A latch as defined in claim 3 in which said cam surface is formed atthe intersections of said curved and outwardly extending portions ofsaid guide slot and extends across the intersection between the curvedand outwardly extending portions of said slot in said bolt when saidlever is in said active position.

5. A latch as defined in claim 2 in which the end of the curved portionof one of said slots engages said guide member when said outer end movesbeyond said extended position without engaging the strike.

6. A latch as defined in claim 3 in which said outwardly extendingportion of said guide slot has a width slightly greater than the widthof said guide member but less than the width of the outwardly extendingportion of the slot in said bolt.

7. In combination with a cabinet having an access opening, a door forclosing the opening, and a strike on the door for latching the door in aclosed position adjacent the cabinet, the improvement comprising, alatch having a base mounted within the cabinet, an operating handlepivoted on said base for swinging about a first axis between angularlyspaced unlatched, latched and tight-sealing positions, a latching boltmounted on said handle for swinging relative to the latter about asecond axis to move first along the front of the cabinet from aretracted position to an extended position in engagement with the strikeas said handle is swung from said unlatched position to said latchedposition, and then to move inwardly from said extended position to alatching position as said handle is swung from said latched position tosaid tight-sealing position thereby to draw the door inwardly toward thecabinet, a lever pivoted on said bolt and swingable about a third axisbetween a normal active position blocking inward movement of said bolttoward said latching position and an inactive position permitting suchinward movement, coacting guide elements formed on said bolt and saidlever, and a guide member on said base engaging said elements to guidesaid bolt between its positions and operable in response to engagementof said bolt vviththe strike and initial movement of said bolt'from saidextended position toward said latching position to cause said lever toswing to said inactive position. 1

8. A latch as defined in claim 7 in which said guide element on saidbolt is a slot formed with a first portion in which said guide memberprojects as said bolt is moved from said retracted position to saidextended position and with a second portion in which said guide memberprojects as said bolt is moved from said extended position 11 to saidlatching position, and said lever covers said second portion in saidactive position and uncovers said second portion in said inactiveposition.

9. A latch as defined in claim 7 further including a spring acting onsaid lever to urge the later in a first direction about said third axis,acting through said lever and on said bolt to urge the bolt in theopposite direction about said second axis, and acting through said leverand said bolt and on said handle to urge the handle in the firstdirection about said first axis when said bolt is in said extendedposition.

10. A latch as defined in claim 7 further including a spring connectedto said lever and acting on said handle through said bolt to urge thehandle in one direction about said first axis when the handle is in saidlatched position and to urge the handle in the opposite direction aboutsaid first axis when the handle is in said tight-sealing position.

11. In combination with a cabinet formed with an excess opening, a doorfor closing the opening and a strike on the door for latching the doorin a closed position, the improvement comprising, a latch having a basemounted within the cabinet, an operating handle mounted on said base tomove between unlatched, latched, and tight-sealing positions, a boltguided on said base and connected to said handle to move first intoengagement with the strike as said handle is moved from said unlatchedposition to said latched position and then to shift inwardly in responseto engagement with the strike and as an incident to movement of saidhandle from said latched position to said tightsealing position therebyto draw the door inwardly toward the cabinet, a member carried on saidbolt and movable between a normal active position blocking completeinward movement of said bolt and an inactive position permitting suchmovement, and means on said base acting on said member in response toinitial inward movement of the bolt when the latter engages the strikeand causing the member to shift to said inactive position and therebypermit complete inward movement of the bolt.

12. A latch as defined in claim 11 in which said bolt has an outer endengageable with the strike, and said member is carried by said bolt andis spaced inwardly from said outer end sufiiciently far to be free fromengagement with the strike when the outer end engages the strike.

13. A latch as defined in claim 11 in which said member is disposed insaid active position and moves bodily with said bolt as said handle ismoved from said unlatched position to said latched position, said memberbeing mounted for movement relative to said bolt from said activeposition to said inactive position as said handle is moved from saidlatched position to said tight-sealing position and after the boltengages the strike, and further including a spring holding said memberin said active position with a predetermined force and yielding to allowsaid member to move to said inactive position directly in response tothe force developed by engagement of the bolt with the strike togetherwith continued movement of said handle to said tight-sealing position.

14. In a latch for use with a strike, the combination of, a base, anoperating handle mounted on said base for movement between unlatched,latched and tight-sealing positions, a bolt connected to said handle andguided for movement first along a first predetermined path intoengagement with the strike as the handle is moved from said unlatchedposition to said latched position and then for movement relative to saidhandle along a second predetermined path as a result of engagement withthe strike and as an incident to movement of said handle from saidlatched position to said tight-sealing position, and a spring acting onsaid bolt with a predetermined force to hold the bolt for movement alongsaid first path and to restrict movement of the bolt relative to saidhandle along said second path until the bolt engages the strike, andsaid spring yielding and the spring force being overcome directly inresponse to engagement of the bolt with the 12 strike thereby to permitmovement of the bolt relative to said handle along said second path.

15. A latch as defined in claim 14 including a guide member on saidbase, a guide element on said bolt engageable with said member to guidethe bolt for movement along said first path, and said spring acting onsaid bolt in a direction urging said guide element against said memberwhen said handle is moved from said unlatched position to said latchedposition thereby to hold the bolt for movement along said first path.

16. A latch as defined in claim 15 in which said handle is pivoted onsaid base to swing about a first axis and said bolt is pivoted on saidhandle to swing about a second axis, and said spring urges said boltabout said second axis to press said guide element against said guidemember.

17. In a latching unit, the combination of, a latch having a base, anoperating handle mounted on said base for movement between unlatched,latched, and tight-sealing positions, a bolt connected to said handlefor movement along a first predetermined path as said handle is movedfrom said unlatched position to said latched position, a strike movablebetween a first position spaced from said path and a second positiondisposed in said path and engageable with the bolt as said handle ismoved from said unlatched position to said latched position, said strikenormally being disposed in said second position and being operable inresponse to engagement with the bolt to cause the latter to shift frommovement-along said first path to movement along a second predeterminedpath as said handle is moved from said latched position to saidtight-sealing position, and a spring holding said bolt for movementalong said first path and restricting movement of the bolt along saidsecond path when said strike is in said first position and when saidhandle is moved from said unlatched position to said latched positionand toward said tight-sealing position without said bolt'engaging saidstrike, said spring yielding directly in response to engagement of thebolt with the strike to permit movement of the bolt along said secondpath.

18. In a latch for use with an appliance cabinet having an accessopening, a door for closing the opening, and a strike on one of the doorand the cabinet for latching the door in a closed position against thecabinet, said latch comprising, a base adapted for mounting [within] anthe other of the door and the cabinet, an operating handle mounted onsaid base to move between unlatched, latched and tight sealingpositions, a bolt on said base and connected to be moved by said handle,;a pin and slot connectionbetween said base and said bolt with said pinbearing against one edge of said slot to guide said bolt in a firstpredetermined path from an unlatching position to an extended positionto engage the strike as said handle is moved from said unlatchedposition to said latched position, said slot being formed with a portionpermitting [inward] movement of said bolt relative to the base along asecond predetermined path from said extended position to a latchingposition as said bolt engages the strike and as said handle is moved tosaid tight-sealing position, said pin shifting relative to said slot andaway from said one edge into said one portion during movement of thebolt to its latching position relative to the base, a spring acting onsaid bolt and exerting a predetermined force to keep said pin pressedagainst said one edge of said slot when said handle is moved from saidunlatched position to said latched position and toward saidtight-sealing position without the bolt engaging the strike thereby tohold the bolt for movement in said first path and to restrict movementof the bolt relative to the base along said second path to said latchingposition, and the spring force being overcome directly in response tothe force created by engagement of the bolt with the strike thereby topermit relative movement of the pin into said one portion of said slotand to permit movement of said bolt rela- 13 14 live to the base to saidlatching position as said handle 3,189,375 6/ 1965 Getman 292 113 ismoved to said tight-scaling position. 3,259,412 7/1966 Wheeler 292-ll3References Cited STEPHEN J. NOVOSAD, Primary Examiner The followingreferences, cited by the Examiner, are 5 L WOLFE, Assistant Examiner ofrecord in the patented file of this patent or the original P US. Cl.X.R.

UNITED STATES PATENTS 292-66 2,738,211 5/1952 Schlueter 292 1113,005,065 10/1961 Jellies 20061.62 10

